(a) If, after a hearing, the Commission finds that a violation or violations have occurred, it shall affirm or modify its order previously issued, or issue an appropriate order or orders for the prevention, abatement, or control of the emissions or discharges involved or for the taking of such other corrective action as may be appropriate.

(b) Any order issued as part of a notice or after hearing may prescribe the date or dates by which the violation or violations shall cease and may prescribe timetables for necessary action in preventing, abating, or controlling the emissions or discharges.